Guardiola, who has managed Barcelona and Bayern Munich, told a news conference ahead of the Premier League match with Huddersfield Town that it is part of the culture in other countries.

Asked if he had sent anyone to spy on another team during his career, Guardiola said: "In other countries everybody does that. They are open. When I was training in Munich there were people on the mountain [overlooking training] with cameras and long lenses watching what we were doing. Everybody does it.

"It's the culture of all the clubs, not just the previous ones where I worked. It was a part of the club. But I'm not going to send someone to Huddersfield if that is the question."

Guardiola and former Athletic Bilbao boss Bielsa were rivals during their time in La Liga and Guardiola once joked that Bielsa knew more about his Barca team than he did.

"My respect remains the same," Guardiola said. "He was clear in his statement. I admired what he did in the past, why should I change my opinion. It remains the same. I understand [Derby coach] Frank Lampard's position too.

"It was impossible to look at us at Barcelona. The story is true. No manager has the amount of information he has for every single game, every season. It is unique."

Meanwhile, Benjamin Mendy has returned to training after being out since November with a knee injury, although he is not in contention to face Huddersfield on Sunday.

The French defender also missed the bulk of last season with midfielders Fabian Delph and Oleksandr Zinchenko filling in and Guardiola admitted City will look at more suitable backups during the summer transfer window.

"Mendy is closer but not for this weekend," he said. "It was the third or fourth training session with the team and he is training incredibly well. Now it's time to get in his best condition."

Asked about signing left-back cover, Guardiola added: "We survived well last season, this season too. But we are thinking about that, yes.

"I cannot assure you as I'm delighted with the players I have and at the end of the season we are going to decide. But we are going to look at both options on the table."